Taking your questions briefly:-
3) Choose kit that you like working on
1) But not so much in recent years
2) But other potential customers are available (eg,
vets, small repair companies, etc.
3) It doesn't have
to be medical equipment!
4) If it's out of date ... better let Huw know!
At the end of the day (there's a meaningless phrase for you) you need to make up your own
mind about all this stuff. Another bit of advice I could offer would be:- why not take this opportunity to ponder what it is you really
want (or perhaps, need) to do ... and then follow your star!